In a NOT gate realized with a relay coil and a normally closed contact, which statement is true about how the coil current relates to the input?

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Multiple Choice

In a NOT gate realized with a relay coil and a normally closed contact, which statement is true about how the coil current relates to the input?

In a relay-based NOT gate, the coil and a normally closed contact create inversion because the coil’s state directly controls the contact. The input drives the coil: when the input is true (voltage present), the coil energizes and opens the normally closed contact, cutting the output. When the input is false (no voltage), the coil stays de-energized, the NC contact remains closed, and the output is allowed to pass. This opposite behavior—coil energized for a true input, output inverted—is what makes the NOT operation work with a relay.

In a relay-based NOT gate, the coil and a normally closed contact create inversion because the coil’s state directly controls the contact. The input drives the coil: when the input is true (voltage present), the coil energizes and opens the normally closed contact, cutting the output. When the input is false (no voltage), the coil stays de-energized, the NC contact remains closed, and the output is allowed to pass. This opposite behavior—coil energized for a true input, output inverted—is what makes the NOT operation work with a relay.

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